Rotary loop takers



June 30, 1964 c. M. GRABOWSKI 3,139,050

ROTARY LOOP TAKERS Filed May 24, 1962 In ven tor Char/es /Z Grabo ws/rz' United States Patent 3,139,650 ROTARY LGQI TAKERS Charles M. Grahowsiii, Eeverly, Mass, assignor to United Shoe Machinery Qorporation, Boston, Mass, :1 corporation of New Jersey Filed May 24, 1%2, Ser. No. 197,539 11 Claims. (Ql. 112--33) The present invention relates to lock stitch sewing machines similar to those disclosed in United States Letters Patent No. 1,169,909, granted February 1, 1916, in the name of Fred Ashworth and United States Letters Patent No. 2,271,611, granted February 3, 1942, in the names of Fred Ashworth and Carl F. Whitaker, and more particularly to a novel rotary loop taker therefor.

As fully illustrated and described in the above referenced patents, the rotary loop taker of a lock stitch sewing machine essentially comprises a loop taking portion or beak and a drive engaging portion. The function of the loop taking portion or beak is to engage a loop of waxed thread presented thereto by a loop spreader and needle and to pass the loop around a stationary bobbin encased Within the rotary loop taker. The rotary loop taker and, consequently, the beak portion thereof are rotated at relatively high speed during the operation of the machine and, therefore, the intermittent engagement of successive waxed thread loops by the beak portion results in a progressive wearing away of the throat of the beak or loop taking portion.

The rotary loop takers previously employed in lock stitch sewing machines have been characterized by a loop taking portion or beak integrally joined to a drive engaging portion. Thus, it was necessary to discard the entire rotary loop taker once the loop taking portion was worn to an extent which rendered it inoperative or unfit for future use. Repair of the rotary loop taker by the removal of the worn beak and the attachment of a new beak has not proven feasible. Attempts to attach a new eak by welding have resulted in distortion of the area adjacent to the weld and produced weldments not possessing the required strength to insure a life for the repaired loop taker sufficient to warrant the cost of repair.

Accordingly, the principal object of the present invention is to provide a rotary loop taker having a drive engaging member and a replaceable loop taking portion or beak mountable on the drive engaging member such that the beak portion can be easily replaced without discarding the entire rotary loop taker.

Another object of the subject invention is to provide a drive engaging member and a replaceable beak mountable thereon which can be readily joined in such a manner as to insure proper alincment of the said members. A further object is to provide means whereby the above mentioned members can be firmly locked in position to insure their continued alinement during operation of the machine. A still further object of the invention is to provide means to facilitate the insertion of the bobbin or thread case into the rotary loop taker with greater ease and accuracy than heretofore.

To this end and in accordance with a feature of this invention, there is provided a rotary loop taker in which a bobbin case is supported, the rotary loop taker having an annular drive engaging member and a replaceable loop taking member having a thread engaging beak thereon mountable on the drive engaging member.

The above and other features of the invention, includ ing novel details of construction and combination of parts, will now be described in the following specification and will be pointed out in the appended claims.

in the drawings,

FIG. 1 is a view in right side elevation of a portion Patented done 30, T96 5 of a sewing machine embodying the features of the present invention;

FIG. 2 is a plan view of the loop taker illustrated in FIG. 3 is a sectional view of the loop taker illustrated in PEG. 2, taken along the line III-lII; and

FIG. 4 is an exploded view showing the component members prior to assembly.

The machine illustrated in the drawings is of substantially the same construction and manner of operation, except as hereinafter pointed out, as that disclosed in the patents referred to above. The machine includes a curved hook needle 19, a needle guide 12, a work support 14, a presser foot 16, a thread case or bobbin 2%, a loop spreader (not shown), and a rotary loop taker, generally indicated by the reference number 40 in FIGS. 1, 2 and 3.

The novel rotary loop taker 40 has the general form of a cylinder which is rotatably supported on the frame of the machine 3t) by means of a two-part circular guide plate 32 engaging a guiding groove or raceway 42. formed on the exterior surface of the rotary loop taker. The loop taker as also has a guiding groove or raceway 44 formed on the inner surface thereof for supporting the thread case or bobbin 20. The raceway 44 is engaged by a circular flange 22 on the periphery of the thread case which is discoidal in shape.

The thread case or bobbin 20 is held in a stationary position within the rotary loop taker by a pair of alter nately reciprocating pins or fingers 34, 34 slidingly mounted in a stationary casing 36 secured to the frame of the machine and engaged by a rat-trap spring 38 to force the pins into slots at one end of the thread case, each pin being lifted to permit passage of the needle loop across the end of the thread case as hereinafter described. The rotary loop taker has a loop taking or beak portion thereon arranged to enter each needle loop and to carry said loop about the bobbin 2!) without itself passing through the loop.

As illustrated in FIGS. 2, 3 and 4, the rotary loop taker dd comprises a drive engaging member 50, a replaceable beak or loop taking member 60, and a detachable bobbin retaining member 76. The three above-mentioned members are formed and joined in such a manner as to permit interchangeability of the beak member while insuring ease in assembly and manufacture and maintenance of alinement during operation.

The drive engaging member 50 of the rotary loop taker 4b is an annular member having bevel gear teeth 51 cut circumferentially upon the exterior surface thereof and having a mounting surface 53 for the beak member 50 and the bobbin retaining member 7 0.

The rotary loop taker 40 is rotated continuously during operation of the machine by means of a cooperating gear (not shown) meshing with the bevel gear teeth 51 on the rotary loop taker 4t) and connected to a drive shaft in a manner similar to that disclosed in the patents referenced above. The fingers 34, 34 mounted in the casing 36 are alternately lifted from the slots in the thread case 20 by means of a cam surface 52 located on the end of the drive engaging member 50 adjacent to the bevel gear teeth 51. The cam surface 52 is disposed along a portion of the circumference of the drive engaging member 59 and alternately contacts projections on the pins 34, 34- during each revolution of the drive engaging member, thereby resulting in alternate reciprocation of the pins 34, 34 to permit passage of the needle loop across the end of the bobbin ill.

The loop taking or beak member 60 is mountable on the drive engaging member 50 in a recess formed in the mounting surface 53 thereof. As illustrated in FIGS. 2, 3 and 4, the beak member has a stud 61 extending from a finger 62 on the base thereof. The stud 61 is engageable within a hole 54 in the drive engaging member 50 to provide a pivotal mounting of the beak member 60 on the drive engaging member 50 for rotative movement into and out of operative position thereon. The beak member 60 is guided into proper operative position on the drive engaging member 50 by a mounting means formed by an undercut tongue or T-member 55 located on the recessed portion of the mounting surface 53 and a cooperating groove or T-portion 63 formed in the beak member 60. The ends of the T-member 55 and T-portion 63 are preferably arcuate and concentric with the hole 54 thereby facilitating and guiding the pivotal movement of the beak member 60; it being clearly understood however, that any complementary cooperatively disposed ends which permit pivotal movement of the beak member may be employed. The operative position of the beak member 60 is determined by contact of a surface 64 on the beak member with a surface 56 on the drive engaging member, the surface 56 and the surface 64, with the beak member in operative position, being angularly disposed relative to an intersecting radius line of the drive engaging member 50. When the beak member is in operative position, it is secured therein by a screw 46 passing through a lip 67 and into the drive engaging member.

The beak member 60 is mountable on the drive engaging member 50 in such a position as to form an opening in front of the beak 65 to receive that portion of the needle loop which is passed behind the bobbin case. In the operation of the machine, a thread loop passes through said opening and is received in a throat portion 68 of the loop taking member 60 which carries the bight of the loop about the thread case or bobbin 20. The beak member 60 and the drive engaging member 50 mutually form the guiding groove or raceway 42 in the recessed portion of the mounting surface 53. The re maining portion of the raceway 42 is located in the drive engaging member intermediate the bevel gear 51 and the mounting surface 53. The beak member 60 has a shoulder or rib 66 on the exterior surface thereof which engages one leg of the needle loop and assists in passing this leg of the loop across the thread case 26.

To enable the flange 22 on the bobbin case 20 to be inserted into the guiding groove or raceway 44 without the necessity of removing the beak member 60, a portion of the raceway is formed in the detachable bobbin retaining member 70 which is mountable on the raised portion of the mounting surface 53. The raceway 44 is formed in the inner surface of the rotary loop taker 40 by a recessed retaining surface cut in the bobbin retaining member 70 and complementary recessed surfaces cut in the drive engaging member t and lip 67 and by a groove cut in the beak member 60. When the bobbin is initially placed in the rotary loop taker it rests on that portion of the raceway formed by the recessed shoulder in the drive engaging member 50 and by the groove cut in the beak member 60. The bobbin retaining member 70 is thereafter located in position by inserting a stud 71 carried thereby in a hole 57 and is locked in position by screws 47 threaded into the drive engaging member 50.

The rotary loop taker 40 is assembled by initially mounting the loop taking member 60 on the drive engaging member 50 by locating the stud 61 within the hole 54 and thereafter rotating the loop taking member into operative position. The T-member 55, T-portion 63 and surfaces 56 and 64 facilitate easy and accurate location and removal of the lop taking member 60. The loop taking member is then locked in position by inserting the screw 46. At this time the bobbin is placed in position and rests on the recessed shoulder in the drive engaging member 50 and the lower surface of the groove cut in the loop taking member 60. The subsequent attachment of the bobbin retaining member 70 completes the raceway 44, as described above. The bobbin retaining member 70 is located and retained in position by the stud 71 and screws 47. As illustrated in FIGS. 2 and 3, the bobbin retaining member overlaps the lip 67 and, thus, prevents removal of the screw 47 and, therefore, the loop taking member 60 when the bobbin retaining member is in position. The bobbin can be replaced by removing the bobbin retaining member.

aving described my invention, what I claim as new and desire to secure as Letters Patent of the United States 1. A rotary loop taker for use with a Waxed thread sewing machine, comprising an annular drive engaging member having mounting means thereon and a replaceable loop taking and carrying member having a loop entering beak and a throat adapted to carry the bight of a needle loop about the thread case mountable on said drive engaging member for movement thereon, said loop taking member having means tiereon cooperative with said mounting means to guide said loop taking member into and to retain said loop taking member in operative position on said drive engaging member.

2. A rotary loop taker for use with a waxed thread sewing machine, comprising an annular drive engaging member having a recessed mounting surface therein, said recessed mounting surface having mounting means. thereon, and a replaceable loop taking and carrying member having a loop entering beak and a throat adapted to carry the bight of a needle loop about the thread case mountable on said recessed surface, said loop taking member having means thereon cooperative with said mounting means to guide said loop taking member into and retain said loop taking member in operative position on said drive engaging member.

3. A rotary loop taker for use with a waxed thread sewing machine, comprising an annular drive engaging member having a recessed mounting surface formed therein and a replaceable loop taking and carrying member having a loop entering beak and a throat adapted to carry the bight of a needle loop about the thread case mountable on said recessed mounting surface for movement thereon, said drive engaging member and said loop taking member mutually forming an arcuate portion of a circular raceway on the exterior surface of said rotary loop taker.

4. A rotary loop taker for use with a waxed thread sewing machine-comprising an annular drive engaging member, a replaceable loop taking member, and means including a T-shaped projection having non-parallel end portions on one of said members cooperating with a correspondingly shaped T-slot in the other of said members for accurately locating and holding the loop taking member in operative position on said drive engaging member.

5. A rotary loop taker for use with a waxed thread sewing machine, comprising an annular drive engaging member, a replaceable loop taking member, a stud providing a pivotal connection between the loop taking member and the drive engaging member, a T-shaped projection on the drive engaging member engageable in a T-slot in the loop taking member, said T-shaped projection and the T-slot having non-parallel complementary cooperatively disposed engaging surfaces.

6. A rotary loop taker for use with a waxed thread sewing machine, comprising an annular drive engaging member, a replaceable loop taking member, a stud providing a pivotal connection between the loop taking .member and the drive engaging member, a T-shaped projection on the drive engaging member engageable in a T-slot in the loop taking member, said T-shaped projection and the T-slot having arcuate engaging surfaces concentric with the stud, said drive engaging member and said loop taking member having cooperating flat non-radial surfaces to provide a stop for the pivotal movement of the loop taking member when it is moved ks? into operative position about the stud on the drive engaging member.

7. A rotary loop taker for use with a waxed thread sewing machine, comprising an annular drive engaging member having a recessed mounting surface, a replaceable loop taking member having a beak portion mountable on said recessed surface, and means including a T-shaped projection having non-parallel end portions on one of said members cooperating with a correspondingly shaped T-slot in the other of said members for accurately locating and retaining the loop taking member in operative position on said drive engaging member, said loop taking member and drive engaging member mutually forming a loop receiving opening in front of said beak and an arcuate portion of a circular raceway on the exterior surface of said rotary loop taker.

8. A rotary loop taker for use with a waxed thread sewing machine, comprising a drive engaging member having a recessed mounting surface therein, a replaceable loop taking member mountable on said recessed mounting surface, and a detachable bobbin retaining member mountable on said drive engaging member, said drive engaging member, loop taking member and bobbin retaining member cooperatively forming a raceway on the inner surface of said rotary loop taker.

9. A rotary loop taker for use with a waxed thread sewing machine, comprising a drive engaging member having a recessed mounting surface therein, a replaceable loop taking member mountable on said recessed mounting surface, said drive engaging member and loop taking member mutually forming an arcuate portion of a circular raceway on the exterior surface of said rotary loop taker, and a detachable bobbin retaining member mountable on said drive engaging member, said drive engaging member, loop taking member, and bobbin retaining member cooperatively forming a raceway on the inner surface of said rotary loop taker.

10. In a waxed thread sewing machine, a rotary loop taker having a raceway on the inner surface thereof, said rotary loop taker comprising an annular drive engaging member having a recessed and a raised mounting surface thereon, said raised mounting surface having a recessed shoulder on the inner surface thereof, a replaceable loop taking member mountable on said recessed mounting surface for pivotal movement thereon, said loop taking member having a groove on the inner surface thereof cooperatively alined with said recessed shoulder, said recessed shoulder and said groove mutually forming a terminal surface of said raceway, and a detachable bobbin retaining member having a recessed retaining surface on the inner surface thereof, said groove, recessed shoulder, and recessed retaining surface cooperatively forming said raceway.

11. A waxed thread lock stitch sewing machine having, in combination with other stitch forming instrumentalities, a rotary loop taker in which a bobbin case is supported, said rotary loop taker comprising an annular drive engaging member, a replaceable loop taking and carrying member having a loop entering beak and a throat adapted to carry the bight of a needle loop about the thread case mountable on said drive engaging member for movement into and out of operative position thereon, said loop taking member having a beak thereon, and a detachable bobbin retaining member mountable on said drive engaging member in contact with one end of said loop taking member, said drive engaging member, loop taking member and bobbin retaining member c0- operatively forming a loop receiving channel in front of said beak.

References Cited in the file of this patent UNITED STATES PATENTS 649,759 Robinson May 15, 1900 1,824,063 Ashworth Sept. 22, 1931 2,415,484 Haas Feb. 11, 1947 

1. A ROTARY LOOP TAKER FOR USE WITH A WAXED THREAD SEWING MACHINE, COMPRISING AN ANNULAR DRIVE ENGAGING MEMBER HAVING MOUNTING MEANS THEREON AND A REPLACEABLE LOOP TAKING AND CARRYING MEMBER HAVING A LOOP ENTERING BEAK AND A THROAT ADAPTED TO CARRY THE BIGHT OF A NEEDLE LOOP ABOUT THE THREAD CASE MOUNTABLE ON SAID DRIVE ENGAGING MEMBER FOR MOVEMENT THEREON, SAID LOOP TAKING MEMBER HAVING MEANS THEREON COOPERATIVE WITH SAID MOUNTING MEANS TO GUIDE SAID LOOP TAKING MEMBER INTO AND TO RETAIN SAID LOOP TAKING MEMBER IN OPERATIVE POSITION ON SAID DRIVE ENGAGING MEMBER. 